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\begin{equation*} \rho \left({\partial v_x \over \partial t}+ v_x {\partial v_x \over \partial x}+ v_y {\partial v_x \over \partial y}+ v_z {\partial v_x \over \partial z}\right)= \mu \left[{\partial^2 v_x \over \partial x^2}+{\partial^2 v_x \over \partial y^2}+{\partial^2 v_x \over \partial z^2}\right]-{\partial p \over \partial x} +\rho g_x\end{equation*}
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